Find the max. horizontal strain on the hinge

are u asking the for strain or for force!!!

Dear this is a very good question..

Like u need to give the dimensions of the hinge
And the thickness of the nail on the hinge!

Is the answer a function of all those?

In this case the plank with red color shows th einitial position
while the blue shows the final position

Now we need to do an energy balance to find the velocity at the blue position!

initally let potential energy be 0.

so inital energy is 0

finally let omega about the hinge (final) be ω

so 1/2Iω²-mgd/2=0

where d is the depth of the hinge

and I=md²/3

so ω²=mgd/I = 3g/d

..

now what will be the force?

mω²d/2 = 3/2mg